Noise in speakers from Blackberry.

February 28, 2005 1:09 PM

What's up with the noise in speakers when a Blackberry or GSM/GPRS cell phone is nearby?

I have both a Blackberry and a GSM cell phone on my person most all the time, and my company has a large population of Blackberry users, so I'm pretty much surrounded. I find it excurciatingly annoying when I hear a buzzing noise in my PC or car speakers and when talking on my office phone when info is transmitted/sent from either device. Most of the time I can simply relocate the device away from any speakers or microphones and the noise will stop. My web searching has come up pretty dry so far. Is there an explanation for this noise? Is there anything being done to eliminate this problem?

posted by sublivious to Technology (8 answers total)

Previous AskMe question. Basically, there's nothing you can do about it other than better shielding on devices that can pick up the noise, or changing to a different, less bursty wireless standard.
posted by zsazsa at 1:29 PM on February 28, 2005

Best answer: Three links:

Ask.Me 13627
Ask.Me 5612
Wi-fi forum
posted by nobody at 1:36 PM on February 28, 2005

(but, for what it's worth, I couldn't get the google search of the site to find these. An in-house search for "cell phone" worked but there was a lot to weed through.)
posted by nobody at 1:38 PM on February 28, 2005

Random Trivia: In Europe, there was actually a dance music track written which used that buzz-buzz noise as its base.
posted by Mwongozi at 1:46 PM on February 28, 2005

It's called Electro Magnetic Interference (EMI) and is the reason they ask you to turn off cell phones on aircraft. It's also why some people are worried that we're all gonna get brain cancer from cell phones. Those little buggers put out a radio signal that is strong enough to make speaker wires act as antennae.
posted by Doohickie at 2:08 PM on February 28, 2005

I live in an area that is heavily trafficked by military aircraft. Whenever there's an E-2 or AWACS plane in the air, my speakers (computer, car, etc) emit loud "squelch" noises (not clicks). Would that be the same general thing as above?
posted by Hankins at 2:50 PM on February 28, 2005

Doohickie: Don't forget that right now you've probably got a 100 watt transmitter of EM radiation within ten feet of your head!

The fact that the speaker wires pick up audible interference from the phone signal doesn't necessarily speak to the signal's strength. It's possible that a very weak signal of the proper frequency will generate noise. Certainly it's true that many very strong signals won't, which is why the light bulb I was alluding to above doesn't cause any problems.
posted by tss at 4:33 PM on February 28, 2005

Here's a funny corollary to this thread/question: I own a radar/laser detector (which I never use now). Every time my GSM phone says hi to one of its towers (either during handoffs, active calls, or occasionally without any warning at all), it would trigger ... my LASER warning! Apparently the US GSM frequency is some sort of harmonic of the laser frequency...

PS. As for the worry about brain cancer, you probably get more radiation from a single cross-country commercial flight than from bunches of cellphone calls... you know, from that giant nuclear explosion in the sky... :)
posted by socratic at 7:19 PM on February 28, 2005